Optical quantum information processing can be classified into two categories depending on the way of encoding quantum information on light: one harnesses the particle nature (photon)−called discrete-variable approach−, and the other exploits the wave nature (electric field)−called continuous-variable approach. Basic nonclassical lights for the two are single photon and squeezed vacuum, respectively. Recently, a new field of study is emerging, called hybrid quantum information processing that combines the two conventional approaches to complement each other.

In this seminar, I will present generation of non-Gaussian quantum states of multimode light based on the hybrid quantum information processing. Squeezed vacuum, which is employed in the continuous-variable approach, is a Gaussian state, which can be described by moments up to the second order (i.e. variance). However, it has limitations on quantum computing and quantum communication, while single-photon subtraction used in the discrete-variable approach can provide non-Gaussian characteristics. We have implemented a single-photon subtractor compatible with multimode squeezed vacuum and generated non-Gaussian multimode quantum states. The novel quantum states of light will find applications in various quantum technologies such as distillation of entangled states, universal quantum computing, and quantum metrology.